Apparatus for dewatering pulpy material



Sept. 27, 1966 D. P. WALKER APPARATUS FOR DEWATERING PULPY MATERIAL- Original Filed Sept. 50. 1963 INVENTOR Doug/as Priny/e Wa/lrer BY WM.M

HTTORNEY.

United States Patent 3,274,924 APPARATUS FUR DEWATERING PULPY MATERlAlL Douglas Pringle Walker, Rte. 2, Box 160,

Mount Vernon, Washington Continuation of application Ser. No. 312,667, dept. 3t), 1963. This application Nov. 29, 1965, Ser. No. 5ltl,l92

It) Claims. ((31. Mill-i153) Ths application is a continuation of my application Serial No. 312,667, filed Sept. 30, 1963, now abandoned, for Machine for Treating Pit Peat Moss.

This invention relates to apparatus for converting wet peat moss, as it comes from the bog, into a dehydrated commerically utilizable product.

More particularly, the invention relates to apparatus for squeezing wet peat moss and other wet pulpy material to express sufficient moisture from it to reduce the moisture content to a value to meet market requirements, and which apparatus will do this at a rate that is efficient and commercially practical. So far as is known to me, the apparatus of the present invention is the only one which will prepare peat moss direct from the bog to produce an article of manufacture suitable for the market without supplemental heat drying.

To dewater economically peat moss as it comes wet from a peat bog so as to render it marketable presents a difficult problem. Before making my present invention I had tried to remove water from peat moss simply by feeding it between rubber-covered rollers. The best production rate that could be obtained was twenty bags (two cubic feet each) per hour. This yield was so small as to be impractical and to achieve even this production, mos-s had to be almost pure in the deposit. Also, the moss could not be processed directly from the bog but it was necessary to allow it to air dry to lose much of its water for a period of at least two Weeks in sunny weather. This was the maximum yield which could be obtained from such a machine and was not enough to be commercially feasible.

Even the above low yield did not produce a satisfactory finished moss product, i.e. a product which could satisfactorily be packed in standard bales, as it was too wet. Freight charges were too high to permit shipping such wet moss. 'Dhe moss weight should not exceed, on the average, 100 pounds per bale produced from cubic feet of loose moss. Thus, weight becomes a very critical and important factor in merchandising the peat moss.

The apparatus of my invention will produce a minimum of 125 two-cubic-foot bags of marketable moss per hour, or 1000 bags per 8 hours, as compared to an average of 160 bags in 8 hours processed by the machine having rubber-covered rollers of moss not sufficiently dry to be economically marketable. The moss from the apparatus of my invention averages 35 bales per hour each bale formed from ten cubic feet of loose moss of an average weight of 10 pounds per cubic foot.

Among the important features of my invention are the endless wool felt belt plus the perforated metal rollers and the feed control. The angle of downward slope to the horizontal of the feed belt is best at between 20 and 30, preferable 25. This provides a wedging action as the peat moss is fed forward and enables the rollers of my invention to grip the moss and draw it into the rollers as it lies on the wool felt belt.

Attempts to use heat in drying the peat moss are highly objectionable as it destroys or injures one of the main properties of the moss, namely, the property of absorbing moisture. Direct heat from any source, too long exposure to the sun or other heat is very harmful to the mess. it causes an exuding of cellular material which under heat becomes hard and seals off the cell so as to make it lose its ability to absorb and discharge water. This property of absorbing great quantities of water constitutes the property which makes the moss of special value for horticuitural and industrial purposes. The present invention is characterized by its utility in dewatering the wet moss directly from the peat bog.

Stated in summary form, the apparatus of my invention provides for a pair of cooperating top and bottom press rollers, the bottom roller having a hard or metallic perforated surface and the overlying top roller being rubber-coated, and an endless felt belt passing over a rigid backing plate supported stationarily inclined downward toward the nip of the rollers, the belt passing between the rollers to carry moss between them.

To summarize briefly water-soaked peat moss taken directly from the peat bog has a cellular structure infiated with water. Such peat moss is distributed uniformly on the felt belt which overlies and is supported by the plate extending downwardly at an angle of between 20 and 30, preferably 25, to a location close to the nip formed by the pair of cooperating rollers between which the belt passes. The lower one of such cooperating rollers has a perforated periphery so that the water can run down through the same, and the upper roller has a rubber facing. Since the belt-supporting plate extends downwardly a sufficient distance so that its lower end is adjacent to the nip of the rollers, peat moss carried by the belt is first pressed between the upper roller and the lower margin of the belt-supporting plate. The downward inclination of the wool felt belt further provides a wedging action as the peat moss is fed forward and enables the rollers to grip the moss and draw it between the rollers so that it is subjected to a second pressing.

The portion of the wool felt belt immediately ahead of the rollers initially absorbs some of the water squeezed from the imoss passing between the rollers and the water generally is able to escape rapidly through the perforated bottom roller so as to prevent an accumulation of excess water ahead of the rollers which would float moss backward and deter its entrance between the rollers. As the walter laden belt portion passes between the rollers water is squeezed from it as well as from the moss thereon. In my previous experience, water accumulation ahead of two rollers in contact both having rubber surfaces without a felt belt and without other features of the present invention has deterred passage of wet rnoss between such rollers.

The above-mentioned general objects of my invention, together with others inherent in the same, are attained by the mechanism illustrated in the accompanying drawings, the same being a preferred exemplary form of my invention.

FIGURE 1 is a longitudinal vertical section of a machine embodying my invention;

FIGURE 2 is a fragmentary plan of the feeding end of the machine taken on line 2-2 of FIGURE 1;

FIGURE 3 is a fragmentary plan of one side of the machine on line 3-3 of FIGURE 1;

FIGURE 4 is an enlarged elevation of a detail of the apparatus; and

FIGURE 5 is an enlarged vertical section showing a detail of the pressing roller mechanism.

A leveling rotor or distributor 11 in the housing 12 spreads the peat moss as it comes from the peat bog on upward-moving belt 13 in a uniform layer of predetermined thickness. The desired quantity of moss to be fed to the machine, as thus established, is then transferred to the endless, water-absorbent feed belt 14 of wool felt or like material supported upon a rigid downwardly inclined plate 15 with its upturned guiding edges 16. Plate 15 is supported stationarily in a position inclined substantially tangential to the feed side of a top roller 17 and its lower end portion extends beneath the feed side arc of such top roller overhanging the nip of the cooperating top and bottom rollers 17 and 18, and located close to such ni as shown in FIGURES 1 and 5. The wool felt belt and moss carried on such belt are therefore squeezed between the lower end portion of plate 15 and top roller 17. The downward slope of the plate and belt also afford a wedging action on the moss to facilitate its entry between rollers 17 and 18. It has been found that an angle of between 20 and 30, such as 25, to horizontal is preferable. For eflicient operation this inclination is important.

The top roller 17 is rubber-covered, the rubber preferably being of the order of "V inch thick, and the bottom roller 18 is of hollow hard construction, such as of steel, with its surface having perforations 19 to drain away promptly water expressed from the moss carried between the rollers on the felt feed belt 14. The wet peat moss spread on the belt will be lumpy in some degree and so provision is made for top roller 17 to be resiliently mounted on arm 20 pivoted at 21. Upper spring 22 slidably mounted upon upstanding pin 23 bears on arm 20 to depress it while the lower spring 24 mounted on such pin bears upwardly on the arm to cushion the action of spring 22. Such springs are adjustably mounted by nut 25.

I have discovered that the felt belt 14, the top rubbercovered roller 17, the rigid, stationary, downwardly inclined belt-supporting plate 15 extending close to the nip of the rollers and the bottom perforated hard roller 18 are most important in providig eflicient yield which makes the invention economically practical. The squeezing action of upper and lower rubber-covered rollers on wet pulpy material produces an accumulation of water in front of the rollers which water tends to float such material backward and lengthwise of the rollers and deters entry of the material between the rollers. Thus, so low a yield results as to render the use of such rollers on wet material economically impractical. The apparatus of the present invention prevents the accumulation of such water ahead of the rollers because the wool felt material of the feed belt absorbs the initial water expressed from the moss, and the space between the lower end of plate 15 and the bottom roller 18 and the perforations 19 in the periphery of the bottom roller permit the water squeezed from the belt to escape quickly so that the water does not build up in front of the rollers 17 and 18. The belt 14 then continues around rollers 26, 27 and 28 to pass again over plate 15.

The moss, after passing between rollers 17 and 18, drops from felt belt 14 upon feed belt 31 supported on plate 32 to pass over roller 33 in front of a rubber-covered top roller 35 and a perforated bottom roller 34, which top and bottom rollers are of a construction similar to that of rollers 17 and 18, respectively, but may be smaller in diameter so as to exert a more concentrated pressure on the peat moss. Such rollers are superposed, preferably not at right angles to the felt belt 31, because from roller 33 such belt slopes downward toward the rollers 34 and 35. Also a downwardly inclined belt-supporting plate is located immediately ahead of such rollers, extending close to their nip, corresponding to plate 15 ahead of roll- 4 ers 17 and 18. A vessel or other means 36 is located beneath rollers 17 and 18 to catch the water expressed by the same.

From the rollers 34 and 35 the feed belt 31 supported on plate 32' passes between rollers 37 and 38, is supported by a second plate 32 and passes between rollers 39 and 48. The rollers 37 and 38 and rollers 39 and 48 have their peripheries covered with rubber. Rollers 37 and 38 and 39 and 48 may be of the same size as rollers 34 and 35. Rollers 38 and 48 are yieldably mounted on arms 41 and 42 having upper and lower springs 43 and 44 and 45 and 46 respectively disposed on pins 47 and 48. These springs are adjustable by nuts 49 and 58 to vary the pressure between the rollers. Vessels or other means 51 are located beneath the respective pairs of rollers to catch water expressed by said rollers.

Belt-cleaning water sprays 53 and 54, discharged from water supply pipes, are disposed to impinge forcibly on the backs of felt belts 14 and 31, respectively. Cooperating with such cleaning sprays are rotary heaters 55 and 56 which loosen moss adhering to the felt belt and vibrate the belt by striking the front of the belt adjacent to the jets.

The wet peat moss is broken up and distributed uniformly by the mechanism identified as 11 above. The moss is then fed to the felt belt 14, squeezed between the upper roller 17 and lower end margin of supporting plate 15 and then fed to rollers 17 and 18. The lower hollow roller 18, with its hard surface and perforations 19, allows the water to pass through to catcher 36 while the felt belt 14 cooperates in preventing an accumulation of water so that the moss is not floated backwardly from the rollers and thus prevented from entering between the roll ers. The angle of the plate 15 provides a wedge-like action in feeding the moss to the rollers 17 and 18. The rubber on the rubber-covered rollers is of the degree of hardness of about 70-80 Shore durometer.

The roller 17 may yieldingly rise if a hard chunk of peat is encountered by pivoting on resiliently mounted lever arm 28, shown in detail in FIGURE 4, spring 22 contracting to permit the roller 17 to rise. Belt 14 is washed and cleaned by water sprays 53 and beater 55.

The moss then falls upon felt belt 31 on which it is carried between rollers 34 and 35, upper resiliently mounted roller 35 being rubber-covered similar to roller 17 and roller 34 having perforations 34a similar to roller 18. These rollers and the felt belt 31 all cooperate to prevent water accumulation as do rollers 17 and 18.

A third pair of rollers 37 and 38, resiliently mounted, and a fourth pair of resiliently mounted rollers 39 and 48 operate to express more water from the peat moss. The water accumulation problem is not as great ahead of these third and fourth pairs of rollers, both the top and bottom rollers of which are rubber-coated, and the felt belt again absorbs water to prevent its accumulation.

My invention provides for great yield, expediting the escape of the water from the moss without undue breaking of the cells. The felt belt and the perforations in the lower rollers facilitate the removal of the water. While the operation of the apparatus has been discussed with respect to peat moss, such apparatus can also be used in the same manner for dewatering pulp material other than peat moss, such as tomato pulp or citrus pulp, remaining after the juicing operation.

Electric motor 68 supplies power to actuate the disintegrating and distributing mechanism 11 through sprocket wheels 58 and 59 connected by sprocket chain 61. Electric motor through sprocket wheels 62 and 63 connected by chain 64 actuates infeed belt 13.

Electric motor 66 actuates lower roller 18 through sprocket chain 67 and wheel 68 mounted on shaft 78. Sprocket wheel 69 coaxially mounted on shaft 70 with wheel 68 drives roller 73 through chain 71 and sprocket 72 which roller frictionally engages up er roller 17.

Electric motor 74 through its sprocket 75 and chain 77 drives sprocekt 76 mounted on shaft 79 of roller 39. Roller 37 is driven in synchronism with roller 39 by sprocket 78 on shaft 79, chain 81 and sprocket 80 on shaft 82 of roller 37. Similarly, roller 34 is driven by sprocket 83, chain 84 and sprocket 85. Upper rollers 35, 38 and 40 are frictionally-driven idler rolls.

Feed felt belt 14 is driven by the pressure on it of rollers 17 and 18. Likewise, feed felt belt 31 is driven by the pressure on it of rollers 34 and 35, rollers 37 and 38, and rollers 39 and 40.

Beaters 55 and 56 are driven by independent electric motors, not shown.

Electric motor 86, through sprocket wheels 88 and 89 and sprocket chain 90, drives a flufiing rotor 87 which is positioned closely above belt 31 just ahead of roller 40 and tosses the moss compacted by the previous rollers to make it fluffy and give the moisture a better chance to escape from the moss as it passes through the fourth set or pair of rollers 39 and 40. The fluffing rotor 87 is driven at several hundred rpm. to produce the fluffiness of the moss.

The combination of my invention provides for the yield of moss which has suificient moisture in it so that the cellular structure of the moss retains its natural waterabsorbing properties. Therefore, the product yielded by the present invention may be used at once for the absorption of further water and does not require, as some moss yields do, soaking for twenty-four to forty-eight hours. Thus, peat moss processed by the combination of the present invention retains a sufiicient amount of moisture to maintain the cellular structure in its moisture-absorbent condition but is sufiiciently dry to permit packaging or baling so as to be economically marketable.

I claim as my invention:

1. A pulp'dewatering machine comprising a first pair of top and bottom rollers in superposed pressing relationship and rotating in opposite directions, respectively, to provide a feed nip at one side thereof, the top roller being rubber-covered and the bottom roller being of hollow, hard-surfaced construction and perforated, a second pair of top and bottom rollers in superposed pressing relationship located at the discharge side of said first pair of top and bottom rollers and rotating in opposite directions, respectively, to provide a feed nip at the side thereof adjacent to said first pair of top and bottom rollers, both the top roller and the bottom roller of said second pair of rollers being rubber-covered, and water-absorbent belt means passing between the rollers of both pairs of rollers, transporting pulp into the feed nip of the first pair of rollers and also transporting pulp from the discharge side of the first pair of rollers into the feed nip of the second pair of rollers.

2. The pulp-dewatering machine defined in claim 1, in which the water-absorbent belt means includes a first endless water-absorbent belt passing between the rollers of the first pair and a second endless water-absorbent belt passing between the rollers of the second pair and receiving pulp from said first belt.

3. The pulp-dewatering machine defined in claim 2, and belt cleaning means for the first belt including water jets directed against one side of the belt and beater means disposed to impact the other side of the belt substantially directly opposite said water jets for removing pulp residue from the belt.

4. The pulp-dewatering machine defined in claim 2, and a third pair of top and bottom rollers in superposed pressing relationship located between the first pair of rollers and the second pair of rollers and rotating in opposite directions, respectively, to provide a feed nip at the side thereof adjacent to the first pair of rollers, the top roller of said third pair of rollers being rubbercovered and the bottom roller of such pair being of hollow, hard-surfaced construction and perforated, and the second endless water-absorbent belt passing between the rollers of said third pair of rollers as well as between the rollers of said second pair of rollers.

5. The pulp-dewatering machine defined in claim 4, in which the second pair of rollers is disposed lower than the third pair of rollers and the second endless waterabsorbent belt is inclined from the third pair of rollers downward to the second pair of rollers.

6. A peat moss dewatering machine comprising a first pair of top and bottom rollers in superposed pressing relationship, said top roller being rubber-covered and said bottom roller being of hollow, hard-surfaced shell construction having drilled holes through its shell forming perforations communicating from its periphery directly through the center of the roller shell with the inner opposite side of the roller shell for immediate escape of water, a second pair of top and bottom rollers in superposed pressing relationship, an endless felt belt passing between the rollers of each of said pairs of rollers for removing peat moss from said first pair of rollers pressed thereby in the form of a sheet of compacted peat moss, and a fluffing rotor having blades extending across said felt belt, located ahead of said second pair of rollers and rotatable for engagement with the sheet of compacted peat moss on said belt to break it into small pieces for facilitating expressing of water therefrom by its passage between the rollers of said second pair.

7. A peat moss dewatering machine comprising a pair of top and bottom rollers in superposed pressing relationship, said top roller being rubber-covered and said bottom roller being of hollow, hard-surfaced shell construction having drilled holes through its shell forming perforations communicating from its periphery directly through the center of the roller shell with the inner opposite side of the roller shell for immediate escape of water, an endless felt belt passing between said top and bottom rollers for transporting peat moss thereto, means rotating said bottom roller in one direction, and a friction drive wheel engaging the periphery of said top roller and rotated in a direction to turn said top roller in the direction opposite the direction of rotation of said bottom roller.

8. A peat moss dewatering machine comprising a first pair of top and bottom rollers in superposed pressing relationship, said top roller being rubber-covered and said bottom roller being of hollow, hard-surfaced shell construction having drilled holes through its shell forming perforations communicating from its periphery directly through the center of the roller shell with the inner opposite side of the roller shell for immediate escape of water, a second pair of top and bottom rollers in superposed pressing relationship, a first endless f elt belt passing between the rollers of said first pair for supplying peat moss between the rollers of such pair, and a second endless felt belt separate from said first felt belt, passing between the rollers of said second pair and receiving from said first belt peat moss which has passed between the rollers of said first pair for transporting such peat moss to the rollers of said second pair.

9. A pulp-dewatering machine comprising a pair of top and bottom rollers in superposed pressing relationship and rotated in opposite directions, respectively, to provide a feed nip at one side thereof, an endless water-absorbent belt passing between said top and bottom rollers to carry pulp into such feed nip and to absorb water expressed from such pulp, and a rigid belt-supporting plate mounted stationarily at the feed side of said rollers inclined downward toward said rollers at an angle in the range between 20 and 30 degrees to horizontal, underlying the stretch of said belt at the infeed side of said rollers moving into said feed nip for supporting such belt stretch, and said plate having its lower end portion eX- tending toward said rollers beneath the feed side are of said top roller overhanging the nip of the rollers and located close to such nip to back said belt stretch in opposition to pressure exerted by said upper roller on pulp carried by said belt, for squeezing the pulp between said top roller and such belt stretch overlying said plate prior to squeezing of the pulp between said top roller and the portion of said belt overlying said bottom roller.

10. The pulp-dewatering machine defined in claim 9, in which the t-op roller is rubber-covered and the bottom roller is perforated and hollow.

References Cited by the Examiner UNITED STATES PATENTS 26,037 11/1859 Hoffman 100-118 X 35,896 7/1862 Rust 100-121 X 52,203 1/1866 Redlein 100-152 205,758 7/1878 Noye 100-37 325,252 9/1885 Lee 100-153 334,343 1/1886 Brubaker 100-118 X 451,464 5/1891 Dickson 4430 730,195 6/1903 Stoveken 100-121 X 8 10/1903 Scanlan 100-121 X 12/ 1917 Rueping 100-152 2/ 1921 Goodfellow 100-121 12/1923 McDougall 44-29 5/1924 Headson 162-360 12/1925 Burt 44-28 12/ 1931 Kutter 100-121 8/1932 Jackson 100-118 X 7/1947 Chagnon 139-426 11/1954 Kronlund 100-121 X 11/1963 Murray 100-172 X 7/ 1964 Kronlund 134-25 FOREIGN PATENTS 10/ 1961 Australia. 2/ 1945 Norway.

LOUIS O. MAASSEL, Primary Examiner. 

1. A PULP-DEWATERING MACHINE COMPRISING A FIRST PAIR OF TOP AND BOTTOM ROLLERS IN SUPERPOSED PASSING RELATIONSHIP AND ROTATING IN OPPOSITE DIRECTIONS, RESPECTIVELY, TO PROVIDE A FEED NIP AT ONE SIDE THEREOF, THE TOP ROLLER BEING RUBBER-COVERED AND THE BOTTOM ROLLER BEING OF HOLLOW, HARD-SURFACED CONSTRUCTION AND PERFORATED, A SECOND PAIR OF TOP AND BOTTOM ROLLERS IN SUPERPOSED PRESSING RELATIONSHIP LOCATED AT THE DISCHARGE SIDE OF SAID FIRST PAIR OF TOP AND BOTTOM ROLLERS AND ROTATING IN OPPOSITE DIRECTIONS, RESPECTIVELY, TO PROVIDE A FEED NIP AT THE SIDE THEREOF ADJACENT TO SAID FIRST PAIR OF TOP AND BOTTOM ROLLERS, BOTH THE TOP ROLLER AND THE BOTTOM ROLLER OF SAID SECOND PAIR OF ROLLERS BEING RUBBER-COVERED, AND WATER-ABSORBENT BELT MEANS PASSING BETWEEN THE ROLLERS OF BOTH PAIRS OF ROLLERS, TRANSPORTING PULP INTO THE FEED NIP OF THE FIRST PAIR OF ROLLERS AND ALSO TRANSPORTING PUMP FROM THE DISCHARGE SIDE OF THE FIRST PAIR OF ROLLERS IN THE FEED NIP OF THE SECOND PAIR OF ROLLERS. 